Journal of Zhejiang University SCIENCE
(ISSN 1009-3095, Monthly)

2005   Vol. 6B   No. 3   p.208-212

Hydrogenation properties of mechanically milled Mg₂Ni_0.8Cr_0.2-CoO/Al₂O₃ composites

WANG Xiu-li, TU Jiang-ping^*, CHEN Chang-pin, ZHANG Xiao-bin, ZHAO Xin-bing

(Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China)
^*E-mail: tujp@zju.edu.cn
Received May 14, 2004; revision accepted Aug. 24, 2004

Abstract: Mg₂Ni_0.8Cr_0.2-x wt.% CoO/Al₂O₃ (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg₂Ni_0.8Cr_0.2 alloy and CoO/Al₂O₃ compound for 45 h. The addition of CoO/Al₂O₃ compound resulted in the good kinetics properties of hydriding/dehydriding reaction of the composites. The composite with 1.0 wt.% CoO/Al₂O₃ catalyst could reach the maximum hydrogen absorption capacity (2.9 wt.%) within 5 min at 393 K under H₂ pressure of 4 MPa, and can desorb rapidly at 493 K. The decomposition and synthesis of hydrogen molecule on Mg₂Ni_0.8Cr_0.2 alloy surface was promoted by addition of CoO/Al₂O₃ catalyst. In addition, the formation of metallic Ni particles, strain and defects during the ball milling process also resulted in the improved hydrogenation performance of Mg₂Ni-based alloys.

Key words: Mg₂Ni-based composite, Hydrogen storage, Ball milling, Catalyst, Hydriding/dehydriding kinetics
doi:10.1631/jzus.2005.B0208             CLC number: TG139.7